A reciprocating saw is a cutting tool with a saw blade which is driven to perform reciprocating movement during operation, typically known as circular saw, saber saw, scroll saw, and etc., and the saw blade of which is generally elongate shaped. Commonly a reliable and easy operable blade clamping device is one of the most important part of a reciprocating saw for allowing the saw blade to be replaced, removed or repaired as and when required.
A cam is normally used in a clamping device for clamping the blade. In such a case, when the blade needs to be replaced, the operator should rotate the cam to a releasing position and take away the damaged blade, and then place a new one instead. Thereafter, the cam will clamp the blade tightly when the operator releases the cam subsequently. But the cam couldn't remain on its releasing position without continuously force applied on it. In other words, the hand of the operator shouldn't leave the cam or the device which is connected with the cam to keep the cam in releasing position. Obviously, such a clamping device which is only available for the blade to be replaced with two hands is not convenient for use. U.S. Pat. No. 5,946,810 disclosed a blade clamping device which could be kept in releasing position such that it is much more convenient for a blade to be replaced. But the shortcoming is the claming is not reliable enough which may result in swing of the blade during the operation. U.S. Pat. No. 6,612,039 disclosed a blade clamping device which is much more reliable, and is able to be hold in its releasing position, while the inconvenience in assembly and manufacture brought by the complex structure causes high cost.